Improvised explosive devices (“IEDs”) are insidious tools used by terrorists and insurgents that can cause injury or death to armed service personnel and civilians. Typically constructed with common, inexpensive components, IEDs can be hidden along roads, in vehicles, in buildings, and many other locations, and, thus can hinder the ability of troops to maneuver effectively in combat zones. Most IEDs employ radio receivers and/or low-cost electronic circuits that allow for remote detonation. Critical to reducing the threats posed by IEDs is the development of systems and methods that allow for effective detection and location of IEDs from safe distances.
Active electronic devices radiate or emit electromagnetic energy either intentionally or unintentionally, and these emissions can be used to detect and locate electronic devices from which these emissions are being emitted. One conventional method for detecting the presence of an electronic device involves using a so called “bug scanner” or non-linear junction detector. The non-linear junction detector detects non-linear junctions such as would be found in an electronic device containing a semiconductor. The non-linear junction detector transmits a signal and receives harmonics of the transmitted signal that are re-radiated by a non-linear junction. This technology can be difficult to use in a noisy environment due to the large number of non-linear junctions that are responsive to this type of stimulation. For example, a rusty nail can respond in the same manner as an electronic device. In addition, such bug scanners must be used in very close proximity to the device or at an extremely high power level. As a result, bug scanners are not an effective means for detecting IEDs because the operator must be in close proximity to the IED, which can place the operator at risk of injury or death, and because it may be impractical or impossible to obtain the desired power level required to operate the bug scanner at safer distances when it is being used in remote areas.
Other conventional systems have been designed to determine if a known electronic device is active. For example, such systems can be used to determine if a cell phone has been powered on during a flight on an airplane. However, this detection technology involves exploiting the knowledge of intentional electromagnetic emissions to identify the active electronic device and would not function for a device that does not intentionally emit electromagnetic emissions like an IED.
There are various industrial and defense applications that would greatly benefit from identifying and classifying electronic devices using their unintended emissions. For example, the detection of unauthorized devices aboard airplanes or the detection of improvised explosive devices (IEDs) in noisy ambient environments are examples of such applications.